1 files changed, 101 insertions, 0 deletions
diff --git a/src/jvm/clojure/runtime/PersistentHashMap.java b/src/jvm/clojure/runtime/PersistentHashMap.java
new file mode 100644
index 00000000..f4ac6330
--- /dev/null
+++ b/src/jvm/clojure/runtime/PersistentHashMap.java
@@ -0,0 +1,101 @@
+/**
+ *   Copyright (c) Rich Hickey. All rights reserved.
+ *   The use and distribution terms for this software are covered by the
+ *   Common Public License 1.0 (http://opensource.org/licenses/cpl.php)
+ *   which can be found in the file CPL.TXT at the root of this distribution.
+ *   By using this software in any fashion, you are agreeing to be bound by
+ * 	 the terms of this license.
+ *   You must not remove this notice, or any other, from this software.
+ **/
+
+package org.clojure.runtime;
+
+import java.util.Iterator;
+
+public class PersistentHashMap implements IMap, Iterable{
+
+IMap impl;
+static final int CAPACITY_THRESHOLD = 42;
+
+public PersistentHashMap(Object[] init){
+    if(init.length/2 < CAPACITY_THRESHOLD)
+        impl = createArrayMap(init);
+    impl = createHashtableMap(init);
+}
+
+public PersistentHashMap(int initialCapacity){
+    if(initialCapacity < CAPACITY_THRESHOLD)
+        impl = createArrayMap();
+	else
+        impl = createHashtableMap(initialCapacity);
+}
+
+PersistentHashMap(IMap impl){
+    this.impl = impl;
+}
+
+public int count() {
+    return impl.count();
+}
+
+public boolean contains(Object key) {
+    return impl.contains(key);
+}
+
+public IMapEntry find(Object key) {
+    return impl.find(key);
+}
+
+public IMap add(Object key) {
+    return put(key, null);
+}
+
+public IMap put(Object key, Object val) {
+    IMap newImpl = impl.put(key,val);
+    if(newImpl.capacity() == CAPACITY_THRESHOLD)
+        {
+        newImpl = createHashtableMap(((ArrayMap)newImpl).array);
+        }
+    return create(newImpl);
+}
+
+public IMap remove(Object key) {
+    IMap newImpl = impl.remove(key);
+    if(newImpl != impl)
+        return create(newImpl);
+    return this;
+}
+
+public Object get(Object key) {
+    return impl.get(key);
+}
+
+public int capacity() {
+    return impl.capacity();
+}
+
+public Iterator iterator() {
+    return ((Iterable)impl).iterator();
+}
+
+public IMap create(IMap impl) {
+    return new PersistentHashMap(impl);
+}
+
+public ArrayMap createArrayMap(Object[] init) {
+    return new ArrayMap(init);
+}
+
+private IMap createArrayMap() {
+    return new ArrayMap();
+}
+
+private IMap createHashtableMap(Object[] init) {
+    return new HashtableMap(init);
+}
+
+private IMap createHashtableMap(int initialCapacity) {
+    return new HashtableMap(initialCapacity);
+}
+
+}